Determining the usefulness of Capsule Scoring of Ulcerative Colitis in predicting relapse of inactive ulcerative colitis

Background and Aim: The usefulness of second-generation colon capsule endoscopy (CCE2) in ulcerative colitis (UC), especially in clinically inactive patients, has been reported. Capsule Scoring of Ulcerative Colitis (CSUC) was developed as a severity index for UC. We aimed to determine whether CSUC is useful for predicting relapse during clinical remission. Methods: Forty-one UC patients in clinical remission who underwent CCE2 were prospectively registered from April 2016 to August 2019. Patients' CSUC score was obtained; those with subsequent relapse were followed up retrospectively. The correlation of CSUC with white blood cell count, platelet count, albumin, C-reactive protein, fecal calprotectin and fecal lactoferrin levels, and fecal immunochemical test results was evaluated; their predictive values for future relapse were compared. Results: The correlations of CSUC with white blood cell, platelet, albumin, C-reactive protein, fecal calprotectin, fecal immunochemical test, and fecal lactoferrin values were r_s = 0.13, 0.27, −0.25, 0.15, 0.50, 0.43, and 0.50, respectively. CSUC was higher in 12 patients who relapsed within 1 year than in 29 patients who remained in clinical remission (2.83 ± 1.95 vs 0.72 ± 1.00, P < 0.01). Receiver operator characteristic curve analysis showed that CSUC ≥ 1 was a predictor of relapse (area under the curve of 0.82, sensitivity of 83.3%, specificity of 58.6%) and maybe superior to fecal biomarkers. In the univariate analysis, patients with CSUC of 0 had a lower relapse rate than those with CSUC of ≧ 1 (P = 0.03, log–rank test). After analyzing patients who underwent CCE2 within 6 months after the successful induction treatment, results showed that those with CSUC of ≤ 1 remained in clinical remission for a year. Conclusion: CSUC predicts relapse within 1 year in UC patients in clinical remission, especially when used 6 months after induction treatment.